Though I have been told by a Nissan mechanic to go to the D-22
It's funny you say that, I had our local Nissan mechanic say the same. "get a 22, the d40 will be back with problems".
So I did, I've got a 22 and my dad has a d40. The d40 is twice the dual cab the 22 is. Sits on 120 no drama, beautiful to drive long distance. The 22 is a lot more ruggered, and it should be, they are a bloody old Ute.
In saying that, the d40 has done a clutch, head, and a lot of little problems. I explain it as "the best dual cab we've ever had and the worst.